Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 345438 times)

Offline princess12

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1095 on: May 17, 2010, 03:46:42 pm »
Is organic chemistry important for paper 6?
no
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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1096 on: May 17, 2010, 03:47:45 pm »
Is organic chemistry important for paper 6?
hey guys i wanted to noe are all neutralisation reactions exothermic.......if no then how do tell wat type of reaction it is????????

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Offline WARRIOR

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1097 on: May 17, 2010, 03:48:45 pm »
they always mention what it is soluble..for ex water-soluble ...or soluble in alcohol

but if they jsut say soluble..then for chromatography u say youse a sotuble solvent
and for  analysis u say water ..i guess
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Offline WARRIOR

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1098 on: May 17, 2010, 03:49:28 pm »
hey guys i wanted to noe are all neutralisation reactions exothermic.......if no then how do tell wat type of reaction it is????????

yes they are exothermic!


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Offline Lariemeeva

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1099 on: May 17, 2010, 03:50:05 pm »
Yup. The study guide says, ALL HYDROXIDES ARE INSOLUBLE EXCEPT GROUP 1 METALS (SODIUM, POTASSIUM ETC), CALCIUM, STRONTIUM AND BARIUM.

Which study guide?

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1100 on: May 17, 2010, 03:50:46 pm »
is preparation of salts as important as identification of ions?

oct/nov 2008 p6

qeustion 7 6 marks all about prep :O
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Offline DEGO

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1101 on: May 17, 2010, 03:51:01 pm »
Which study guide?

Question: When we say a substance is soluble, we mean that it dissolves well in water or all other solvents?
water i guess
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Offline Ghost Of Highbury

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1102 on: May 17, 2010, 03:52:43 pm »
water i guess

Any liquid solvent.
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Offline Shazizzzle

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1103 on: May 17, 2010, 03:53:11 pm »
Which study guide?

The IGCSE Study Guide for Chemistry, Bob Berry, Hodder Education.
A more precise and to-the-point version of the original Hodder Education IGCSE Chemistry book, the Earl and Wilford one.
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Offline Lariemeeva

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1104 on: May 17, 2010, 03:58:17 pm »
^I would have asked if there is an online ver. but it seems too good to be free, although I would have bought it or something, it's probably no use while my exam is tomorrow...Thanks anyways.

Also, can you list down all the solubles and insoluble again? This time a full list after all the corrections...

Another question, if hydrated means that it contains water then it is the same as when we say that a salt is in aqueous form right? Which means it's soluble.

So if this is right then Hydrated = Soluble/Aqueous form?
« Last Edit: May 17, 2010, 04:04:03 pm by Lariemeeva »

Offline NidZ- Hero

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1105 on: May 17, 2010, 03:59:59 pm »
hey can any1 help me hw do we noe a substance is good dehydrating agent or hydrating agent hw can we prove it  n can any1 list dem down  :)

Offline Shazizzzle

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1106 on: May 17, 2010, 04:05:33 pm »
^I would have asked if there is an online ver. but it seems too good to be free, although I would have bought it or something, it's probably no use while my exam is tomorrow...Thanks anyways.

Also, can you list down all the solubles and insoluble again? This time a full list after all the corrections...

-All Chlorides, bromides and iodides are soluble except lead chloride/bromide/iodide, silver Cl/Br/I, and mercury Cl/Br/I

-All sulphates are soluble except lead sulphate, barium sulphate and calcium sulphate

-All carbonates are insoluble except Sodium, potassium (All group 1 metals in general) and ammonium carbonates, which are soluble.

-All hydroxides are insoluble except Sodium, potassium(All group 1 metals in general), ammonium, calcium, strontium and barium hydroxides, which are soluble.

-All nitrates are soluble

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Offline NidZ- Hero

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1107 on: May 17, 2010, 04:05:49 pm »
^I would have asked if there is an online ver. but it seems too good to be free, although I would have bought it or something, it's probably no use while my exam is tomorrow...Thanks anyways.

Also, can you list down all the solubles and insoluble again? This time a full list after all the corrections...

Another question, if hydrated means that it contains water then it is the same as when we say that a salt is in aqueous form right? Which means it's soluble.

So if this is right then Hydrated = Soluble/Aqueous form?

hey can any1 help me hw do we noe a substance is good dehydrating agent or hydrating agent hw can we prove it  n can any1 list dem down 

Offline NidZ- Hero

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1108 on: May 17, 2010, 04:09:40 pm »
hey can any1 help me hw do we noe a substance is good dehydrating agent or hydrating agent hw can we prove it  n can any1 list dem down  :)
   hey can any1 plz help i realli in a state of big confusion :)

Offline Shazizzzle

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1109 on: May 17, 2010, 04:11:04 pm »
^I would have asked if there is an online ver. but it seems too good to be free, although I would have bought it or something, it's probably no use while my exam is tomorrow...Thanks anyways.

Also, can you list down all the solubles and insoluble again? This time a full list after all the corrections...

Another question, if hydrated means that it contains water then it is the same as when we say that a salt is in aqueous form right? Which means it's soluble.

So if this is right then Hydrated = Soluble/Aqueous form?


No, hydrated means it possesses water in its crystals. i.e Water of crystallisation.
Meaning, water was present inside the crystal granules.

Aqueous is when a salt is dissolved in water. i.e it is a solution.

Hydrated salts may not be soluble.
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